Developing a newborn rat model of ventriculitis without concomitant bacteremia by intraventricular injection of K1 (-) Escherichia coli.

BACKGROUND: Neonatal meningitis caused by Escherichia coli results in high mortality and neurological disabilities, and the concomitant systemic bacteremia confounds its mortality and brain injury. This study developed an experimental model of neonatal ventriculitis without concomitant systemic bacteremia by determining the bacterial inoculum of K1 capsule-negative E. coli by intraventricular injection in newborn rats. METHODS: We carried out intraventricular injections 1 × 102 (low dose), 5 × 102 (medium dose), or 1 × 103 (high dose) colony-forming units (CFU) of K1 (-) E. coli (EC5ME) in Sprague-Dawley rats at postnatal day (P) 11. Ampicillin was started at P12. Blood and cerebrospinal fluid (CSF) cultures were performed at 6 h, 1 day, and 6 days after inoculation. Brain magnetic resonance imaging (MRI) was performed at P12 and P17. Survival was monitored, and brain tissue was obtained for histological and biochemical analyses at P12 and P17. RESULTS: Survival was inoculum dose-dependent, with the lowest survival in the high-dose group (20%) compared with the medium- (67%) or low- (73%) dose groups. CSF bacterial counts in the low- and medium-dose groups were significantly lower than that in the high-dose group at 6 h, but not at 24 h after inoculation. No bacteria were isolated from the blood throughout the experiment or from the CSF at P17. Brain MRI showed an inoculum dose-dependent increase in the extent of brain injury and inflammatory responses. CONCLUSIONS: We developed a newborn rat model of bacterial ventriculitis without concomitant systemic bacteremia by intraventricular injection of EC5ME.

Necrotizing Ventriculitis in Fledgling Chimney Swifts (Chaetura Pelagica) Associated With a Novel Adenovirus, Chimney Swift Adenovirus-1 (CsAdV-1).

Five chimney swift fledglings died following a progressive loss of appetite and condition while being cared for by an experienced wildlife rehabilitator. All animals had severe necrotizing and heterophilic ventriculitis, with myriad epithelial cells characterized by karyomegaly with intranuclear inclusion bodies. Transmission electron microscopy showed distention of epithelial cell nuclei and chromatin peripheralization by nonenveloped, icosahedral, 75- to 85-nm-diameter virions. Degenerate nested PCR for a highly conserved region of the adenovirus DNA polymerase gene was positive. BLAST analysis of the amplicon sequence indicated the presence of a novel adenovirus, with 74% homology to Antarctic penguin adenoviruses and 72% homology to a bat adenovirus, at low query coverages of only 65% and 63%, respectively. BLAST analysis of the predicted amino acid sequence generated the highest scores for squamate adenoviruses at 100% query coverage. Based on phylogenetic analysis of the partial amino acid sequence of the DNA polymerase, the chimney swift virus was a novel adenovirus most closely related to the Atadenovirus genus. Using a probe based on the novel viral sequence, DNA in situ hybridization identified viral nucleic acid in the nucleus. While the tentatively named chimney swift adenovirus-1 (CsAdV-1) is so far classified with the Atadenoviruses, it is relatively divergent from other members of that genus and may represent the first identified member of a new genus of Adenoviruses.

Complement system activation contributes to the ependymal damage induced by microbial neuraminidase.

BACKGROUND: In the rat brain, a single intracerebroventricular injection of neuraminidase from Clostridium perfringens induces ependymal detachment and death. This injury occurs before the infiltration of inflammatory blood cells; some reports implicate the complement system as a cause of these injuries. Here, we set out to test the role of complement. METHODS: The assembly of the complement membrane attack complex on the ependymal epithelium of rats injected with neuraminidase was analyzed by immunohistochemistry. Complement activation, triggered by neuraminidase, and the participation of different activation pathways were analyzed by Western blot. In vitro studies used primary cultures of ependymal cells and explants of the septal ventricular wall. In these models, ependymal cells were exposed to neuraminidase in the presence or absence of complement, and their viability was assessed by observing beating of cilia or by trypan blue staining. The role of complement in ependymal damage induced by neuraminidase was analyzed in vivo in two rat models of complement blockade: systemic inhibition of C5 by using a function blocking antibody and testing in C6-deficient rats. RESULTS: The complement membrane attack complex immunolocalized on the ependymal surface in rats injected intracerebroventricularly with neuraminidase. C3 activation fragments were found in serum and cerebrospinal fluid of rats treated with neuraminidase, suggesting that neuraminidase itself activates complement. In ventricular wall explants and isolated ependymal cells, treatment with neuraminidase alone induced ependymal cell death; however, the addition of complement caused increased cell death and disorganization of the ependymal epithelium. In rats treated with anti-C5 and in C6-deficient rats, intracerebroventricular injection of neuraminidase provoked reduced ependymal alterations compared to non-treated or control rats. Immunohistochemistry confirmed the absence of membrane attack complex on the ependymal surfaces of neuraminidase-exposed rats treated with anti-C5 or deficient in C6. CONCLUSIONS: These results demonstrate that the complement system contributes to ependymal damage and death caused by neuraminidase. However, neuraminidase alone can induce moderate ependymal damage without the aid of complement.

Diagnostic accuracy of presepsin (sCD14-ST) for prediction of bacterial infection in cerebrospinal fluid samples from children with suspected bacterial meningitis or ventriculitis.

Children with temporary external ventricular drains (EVD) are prone to nosocomial infections. Diagnosis of bacterial meningitis and ventriculitis in these children is challenging due to frequent blood contamination of cerebrospinal fluid (CSF) and the presence of chemical ventriculitis. The aim of this study was to compare diagnostic accuracy of presepsin (sCD14-ST), a novel biomarker of bacterial infection in CSF, to predict bacterial infection in comparison to the accuracy of established biomarkers like those demonstrated in biochemical analysis of CSF. We conducted a prospective study with 18 children with suspected bacterial meningitis or ventriculitis who had 66 episodes of disease. CSF samples were taken from external ventricular drainage. We measured presepsin in CSF, as well as CSF leukocyte count, glucose, and proteins. CSF was also taken to prove bacterial infection with culture methods or with 16S rRNA gene broad-range PCR (SepsiTest; Molzym, Germany). Infection was clinically confirmed in 57 (86%) episodes of suspected meningitis or ventriculitis. Chemical ventriculitis was diagnosed in 9 (14%) episodes of suspected meningitis or ventriculitis. Diagnostic accuracies presented as area under the curve (AUC) for sCD14-ST, leukocytes, and proteins measured in CSF were 0.877 (95% confidence interval [CI], 0.793 to 0.961), 0.798 (95% CI, 0.677 to 0.920), and 0.857 (95% CI, 0.749 to 0.964), respectively. With CSF culture, we detected bacteria in 17 samples, compared to 37 detected with broad-range PCR. It was found that presepsin was present at a significantly higher level in children with clinically proven ventriculitis than in those without meningitis or ventriculitis. Diagnostic accuracies of presepsin were superior to those of leukocytes or proteins in CSF. Presepsin-guided 16S rRNA gene PCR could be used in everyday clinical practice to improve etiological diagnosis of meningitis and ventriculitis and to prescribe more appropriate antibiotics.

Predominantly periventricular necrotizing encephalitis due to toxoplasmosis: two unusual cases and review of literature.

Ventriculitis or periventriculitis as a predominant pattern of tissue involvement in cerebral toxoplasmosis was always a rare event, even at the height of the acquired immunodeficiency syndrome (AIDS) era. Ventriculitis on premortem neuroimaging or at autopsy in AIDS patients chiefly led to differential diagnoses of primary central nervous system lymphoma (PCNSL) or cytomegalovirus ventriculitis, not toxoplasmosis. Usually cerebral toxoplasmosis manifests as multifocal, necrotizing, hemorrhagic foci of cerebritis or abscesses. We report two non-AIDS patients with cerebral toxoplasmosis that presented with predominant ventriculitis/periventriculitis, with diagnosis in both cases made only at postmortem examination. A 90-year-old woman, with autoimmune hemolytic anemia and large granular lymphocytic leukemia diagnosed 2 1/2 years prior, presented with altered mental status. Neuroimaging revealed a necrotic 5.4 × 4.6 × 3.5 cm mass extending across corpus callosum and involving both periventricular frontal horn regions, diagnosed as "butterfly" glioblastoma or possible PCNSL. No consideration of infection was raised, care was withdrawn. A 44-year-old woman with systemic lupus erythematous (SLE) treated with prednisone presented with fever and generalized malaise with rapid progression to agitation and confusion. Infection was suspected, but never confirmed on extensive premortem workup. Brain autopsy in both patients revealed severe necrotizing toxoplasmosis virtually confined to periventricular regions. In the first case, necrosis extended across the corpus callosum. Large numbers of organisms were found microscopically, reflecting their immunocompromised, and untreated, status. Cerebral toxoplasmosis should be included in the differential diagnosis when encountering patients with necrotizing ventriculitis, even in the non-AIDS immunosuppressed population.

[Infectious ventriculitis in relation with neurocysticercosis in Burkina Faso]. / Ventriculite infectieuse secondaire à une neurocysticercose au Burkina Faso.

INTRODUCTION: Ventriculitis is an uncommon entity, which is defined as localized meningitis in the cerebral ventricles. It usually occurs in a context of immunodepression, where its presence may suggest primary brain lymphoma, certain viral infections including cytomegalovirus (CMV) and much more rarely, tuberculous meningitis. OBSERVATION: A 48-year-old immunocompetent male was admitted to the neurology department of the Ouagadougou teaching hospital with the diagnosis of infectious ventriculitis in relation with neurocysticercosis (NCC). The diagnosis was based on several arguments including brain CT scan (dilated lateral and third ventricles with ependymal enhancement and scattered parenchymatous cystic hypodensities exhibiting enhancement after contrast injection), the notion of exposure (the patient raised pigs), residence in an endemic zone of cysticercosis, and test results: CSF analysis (aseptic meningitis), positive ELISA for NCC in both CSF and blood. The good clinical and biological outcome after treatment with albendazole was another argument favoring the diagnosis. CONCLUSION: This illustrates the importance of searching for NCC in patients with ventriculitis residing in an endemic zone for cysticercosis.

Imaging findings in pyogenic ventriculitis.

INTRODUCTION: Pyogenic ventriculitis is an uncommon but often severe intracranial infection. METHODS: Case report with illustrative CT and MRI imaging. RESULTS: A 49-year-old man presented with an intraparenchymal hematoma with extension of blood into the ventricles. The persistence of intraventricular blood necessitated long term placement of an external ventricular drain. On day 23 after admission, a contrast-enhanced CT scan of the brain showed slight hydrocephalus, irregular debris in the dependent part of the occipital horns and periventricular hypodensities. An MRI scan confirmed the characteristic hallmarks of pyogenic ventriculitis on the T2-weighted, Fluid Attenuated Inversion Recovery (FLAIR), and diffusion-weighted and contrast-enhanced T1-weighted images. CONCLUSION: Neuroimaging is crucial in clearly depicting pyogenic ventriculitis. A contrast-enhanced CT scan, but especially MR imaging, is an ideal tool to reliably diagnose this life-threatening cerebral infection.

Successful Whole Genome Sequencing-guided Treatment of Mycoplasma hominis Ventriculitis in a Preterm Infant.

We report a case of Mycoplasma hominis ventriculitis in a preterm neonate that was successfully identified with 16S ribosomal RNA sequencing and whole genome sequencing after failure to detect the pathogen with conventional diagnostic methods. The infant required doxycycline with subsequent clearance of the infection and no evidence of drug toxicity.

Nosocomial ventriculitis caused by a meticillin- and linezolid-resistant clone of Staphylococcus epidermidis in neurosurgical patients.

BACKGROUND: Postneurosurgical ventriculitis is mainly caused by coagulase-negative staphylococci. The rate of linezolid-resistant Staphylococcus epidermidis (LRSE) is increasing worldwide. AIMS: To report clinical, epidemiological and microbiological data from a series of ventriculitis cases caused by LRSE in a Spanish hospital between 2013 and 2016. METHODS: Cases of LRSE ventriculitis were reviewed retrospectively in a Spanish hospital over a four-year period. Clinical/epidemiological data of the infected patients were reviewed, the isolates involved were typed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing, and the molecular bases of linezolid resistance were determined. FINDINGS: Five cases of LRSE ventriculitis were detected. The patients suffered from cerebral haemorrhage or head trauma that required the placement of an external ventricular drain; spent a relatively long time in the intensive care unit (ICU) (10-26 days); and three out of the five patients had previously been treated with linezolid. All LRSE had the same PFGE pattern, belonged to ST2, and shared an identical mechanism of linezolid resistance. Specifically, all had the G2576T mutation in the V domain of each of the six copies of the 23S rRNA gene, together with the Q136L and M156T mutations and the 71GGR72 insertion in the L3 and L4 ribosomal proteins, respectively. CONCLUSION: The high ratio of linezolid consumption in the ICU (7.72-8.10 defined daily dose/100 patient-days) could have selected this resistant clone, which has probably become endemic in the ICU where it could have colonized admitted patients. Infection control and antimicrobial stewardship interventions are essential to prevent the dissemination of this difficult-to-treat pathogen, and to preserve the therapeutic efficacy of linezolid.

Cell Index in the Diagnosis of External Ventricular Drain-Related Infections.

BACKGROUND: The use of an external ventricular drain is required for the treatment of many diseases, such as traumatic brain injury and subarachnoid hemorrhage (SAH). Meningitis and ventriculitis are frequent complications arising from the use of external ventricular drain therapy. This study aimed to determine the sensitivity, specificity, and cutoff point for cell index (CI) in patients with traumatic brain injury, SAH, and hemorrhagic stroke. METHODS: Our study population consisted of patients with different underlying diseases and few culture-positive cerebrospinal fluid samples. The diagnosis of infection was based on Centers of Disease Control and Prevention criteria. RESULTS: Overall CI analysis showed an area under the curve (AUC) of 0.982. The cutoff of 2.9 for overall CI provided a sensitivity of 95% and a specificity of 92.9%. In patients with SAH, the AUC was 1.0 for a CI of 2.8; furthermore, sensitivity and specificity were 100%. The relative variation of the CI was also assessed. This analysis revealed an AUC of 0.882, and a 4.33-fold increase was found be indicative of infection (P = 0.002), findings similar to those in the literature. In addition, a heatmap analysis demonstrated that the CI is unlikely to return to normal in patients with meningitis, even after treatment. CONCLUSIONS: Therefore, CI is valuable for the diagnosis of infection, but was inadequate for monitoring treatment. We hope to use the new cutoff point proposed by this study in our institution to improve patient clinical outcome.

[Pathognomonic magnetic resonance imaging (MRI) finding of fluid-fluid level in pyogenic ventriculitis: two case reports].

Pyogenic ventriculitis is an uncommon and potentially fatal central nervous system infection. Delayed treatment due to non specific clinical symptoms may lead to an unfavorable outcome. Brain magnetic resonance imaging (MRI) plays an important role in the diagnosis of pyogenic ventriculitis. We describe two patients with pyogenic ventriculitis presenting with a pathognomonic MRI finding. The first patient, a 77-year-old female, developed high fever and consciousness disturbance. MR images revealed hyperintense lesions with a fluid-fluid level in the bilateral lateral ventricles on diffusion-weighted images (DWIs) and hypointense lesions on T2-weighted images (T2WIs). MR images also revealed findings of left otitis media. The second patient, a 63-year-old male, who had a past history of multiple myeloma and had received chemotherapy, developed high fever and left hemiparesis. MR images revealed a hyperintense lesion with a fluid-fluid level in the right lateral ventricle on DWIs and a hypointense lesion on T2WIs, multiple ring-enhancing lesions on gadolinium enhanced T1-weighted images, and pontine infarction on DWIs. Chest computed tomography revealed an infiltrative shadow in the lower lobe of the left lung. On the basis of MRI findings, both patients were diagnosed as having pyogenic ventriculitis and were administered high-dose meropenem intravenously. The second patient was also administered sulfamethoxazole-trimethoprim orally. Intraventricular abnormalities disappeared and the patients achieved complete remission after the antibacterial treatment. Intraventricular hyperintense lesions on DWIs and hypointense ones on T2WIs with a fluid-fluid level is a pathognomonic finding of pyogenic ventriculitis and has not been previously reported in other diseases. Recognition of the characteristic MRI features and initiation of high-dose and appropriate antibiotics in an early stage may lead to a favorable outcome of the disease.

Clinical and magnetic resonance imaging characteristics of tubercular ventriculitis: an under-recognized complication of tubercular meningitis.

BACKGROUND: Ventriculitis also referred as ependymitis or ventricular empyema is a known complication of pyogenic meningitis. Despite high incidence of tubercular meningitis in developing countries, there are hardly any reports of tubercular ventriculitis. METHODS: Five patients (four males and one female) of tubercular ventriculitis were retrospectively identified from December 2007 to August 2013. Their clinical features, cranial MRI characteristics, treatment offered, and outcome were reviewed. RESULTS: The median age of 5 patients was 29 years (range 15 to 64 years). Two patients had preceding pulmonary/pleural tuberculosis and one had Pott's spine. One patient had multi-drug resistant tuberculosis. All five patients had papilledema, four had seizures, two had hemiparesis, and two had vision loss. On cranial MRI all patients showed contrast enhancement of ependymal wall of lateral/fourth ventricle with restricted diffusion and hydrocephalus; three showed intra-ventricular septations with sequestered ventricles, and two had ventricular sludge. Magnetization transfer (MT) images were available in only two patients. Both showed hyperintense epedymal wall on MT images. Four patients required ventriculo-peritoneal shunt and two underwent temporal lobectomy. Two patients with sequestered temporal lobe had acute deterioration in consciousness with signs of impending herniation and required urgent surgical intervention. Four patients recovered on anti-tubercular treatment over 18 months; one receiving secondary line ATT for residual brain abscess. CONCLUSION: Tubercular ventriculitis is a rare complication of tubercular meningitis. MRI feature of sequestered ventricles/intraventricular septations and hyperintense ependymal wall on MT images could suggest tubercular etiology. Symptomatic hydrocephalus may require CSF diversion in most patients.

Successful treatment of multidrug-resistant Acinetobacter baumannii ventriculitis with intrathecal and intravenous colistin.

Acinetobacter baumannii (AB) nosocomial infections, especially those due to multi-drug resistant (MDR) strains, are increasingly detected. We report a case of a 42-year-old male patient affected by low-grade ependymoma who developed AB-MDR post-neurosurgical ventriculitis. Initially, because of in vitro susceptibility, we used a combination of intravenous colistin and tigecycline. This treatment resulted in the improvement of the patient's initial condition. However, soon after, the infection relapsed; tigecycline was stopped and treatment with intrathecal colistin was initiated. Cure was achieved by continuing this treatment for approximately three weeks, without adverse effects.